Abstract

The important question of the segregation of nebulae of different brightness can also only partly be solved until larger Schmidt telescopes are available. In addition, the velocity distribution as a function of the brightness of the nebulae must be investigated. The problems of the segregation of nebulae and of the dispersion in the velocities demand also further theoretical clarification since the classical statistical mechanics gives no answer to the fundamental questions which arise in connection with gravitational cooperative assemblies which are composed of such diverse elements as the nebulae, the stars and the constituents of intergalactic and interstellar matter. The uniformity of the structure of symmetrical clusters of nebulae observed so far and the quantitative agreement of their observed physical characteristics with those derived theoretically for the isothermal gravitational "gas" sphere suggest that the short-time scale associated customarily with the hypothesis of an expanding universe will perhaps become the less attractive the more the investigations on the large-scale distribution of matter in the universe progress.